Write strategy calibration for optical drives

ABSTRACT

Laser write parameters in an optical drive are calibrated. A parameter range for the write parameters is set based on a recordable medium, and a number of test runs are recorded on the recordable medium while varying the write parameters. Write performance characteristics over the test runs are measured. Based on the measured performance characteristics, actual write parameters are selected for use in writing actual data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/022,046, filed Jan. 29, 2008, which claims the benefit of U.S.Provisional Patent Application No. 60/887,255, filed Jan. 30, 2007, thecontents of each of which are hereby incorporated by reference as iffully stated herein.

FIELD

The present disclosure generally concerns the determination of opticallaser drive write parameters for a recordable medium such as a CD orDVD.

BACKGROUND

Optical drives are commonly used to write data to the surface of arecordable medium such as a CD or DVD. Specifically, optical drives usea laser to create “pits” and “lands” on the surface of the recordablemedium, and the pits and lands are detected to reproduce data.

In the optical drive, write strategy parameters determine how the laserwrites to the recordable medium. For example, standard address inpre-groove (ADIP) information on the recordable medium may includerecommended write strategy parameters such as the power of the laser,the tilt of the laser, and so on. Examples of write parameters on acastle waveform are shown in FIG. 5. Nevertheless, a drive developermight believe certain write strategy parameters are optimal, and programsuch parameters into the drive firmware as default values. Consequently,the drive's firmware values may overwrite the parameters from therecordable medium's ADIP information.

In the field, optical drive writing performance often varies due tofactors such as manufacturing differences between optical drives, andbetween recordable media (e.g., a disc type is DVD+R, CD-RW, or BDdouble layer, etc., whereas a brand of disc is Princo, Ricoh, Ritek,Sony, etc.), and differences between disc speeds. For the same reason,it is also ordinarily difficult to compensate for environmentalconditions in the field such as temperature. Thus, write strategyparameters that provide good writing performance characteristics for onemedia may perform poorly when applied to others.

SUMMARY

The foregoing situation is addressed by providing improved writestrategy calibration for optical drives.

Thus, in one aspect, laser write parameters in an optical drive arecalibrated. A parameter range for the write parameters is set based on arecordable medium, and a number of test runs are recorded on therecordable medium while varying the write parameters. Write performancecharacteristics over the test runs are measured. Based on the measuredperformance characteristics, actual write parameters are selected foruse in writing actual data.

Selection can be (1) the best of the predesignated number of test runs,or (2) calibrated based on interpolation of the runs.

Based on design goals, one performance characteristic can be used as aproxy for good overall writing performance, such as jitter, block errorrate (BLER), etc. Alternatively, a composite penalty function can bedefined as a combination of performance characteristics, and theselection is based on the based on the composite penalty function.

By virtue of this arrangement, it is ordinarily possible to improveperformance characteristics of the laser by calibrating multipleparameters of the laser in the field, thus allowing for the writeparameters of the laser to be set and re-set after manufacture accordingto differences in the recording environment.

In another example aspect, laser write parameters in an optical driveare calibrated. There are means for setting a parameter range for thewrite parameters based on a recordable medium, and means for recording anumber of test runs on the recordable medium while varying the writeparameters. There are also means for measuring performancecharacteristics over the test runs. In addition, there are means forselecting actual write parameters for use in writing actual data basedon the measured performance characteristics.

In still another example aspect, a computer-executable programcalibrates laser write parameters in an optical drive. The programcauses the computer to set a parameter range for the write parametersbased on a recordable medium, and to record a number of test runs on therecordable medium while varying the write parameters. The programfurther causes the computer to measure write performance characteristicsover the test runs. Based on the measured performance characteristics,the program selects actual write parameters for use in writing actualdata.

This brief summary has been provided so that the nature of thedisclosure may be understood quickly. A more complete understanding canbe obtained by reference to the following detailed description and tothe attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a disc-writing environment.

FIG. 2 illustrates an example of a process for calibrating parameters ofan optical drive.

FIG. 3 illustrates an example of another process for calibratingparameters of an optical drive.

FIG. 4A is a block diagram showing an example embodiment in a hard diskdrive system.

FIG. 4B is a block diagram of an example embodiment in a DVD drive.

FIG. 4C is a block diagram of an example embodiment in a high definitiontelevision (HDTV).

FIG. 4D is a block diagram of an example embodiment in a vehicle controlsystem.

FIG. 4E is a block diagram of an example embodiment in a cellular ormobile phone.

FIG. 4F is a block diagram of an example embodiment in a set-top box(STB).

FIG. 4G is a block diagram of an example embodiment in a media player.

FIG. 4H is a block diagram of an example embodiment in a Voice-overInternet Protocol (VoIP) player.

FIG. 5 is a diagram illustrating sample write parameters on a castlewaveform.

DETAILED DESCRIPTION

FIG. 1 depicts a simplified example embodiment of a disc-writingenvironment.

Briefly, as seen in FIG. 1, the disc-writing environment includesoptical drive 100 and disc 150. Optical drive 100 comprises laser 101and firmware 102.

Optical drive 100 uses one or more lasers to retrieve and/or store dataon optical discs like CDs and DVDs. More specifically, the laser is usedto encode or “burn” data into the disc by selectively heating parts ofthe disc to form burned “pits” and unburned “lands”. The pits and landscan then be detected in order to read data from the disc. For rewritablemedia, the laser is used to melt a crystalline metal alloy in therecording layer of the disc. Some common types of optical drives includeCD-RW, DVD±RW, and HD-DVD and Btu-ray drives.

Laser 101 is an optical laser used to write data to recordable mediasuch as disc 150. Laser 101 can also read data from disc 150. Forpurposes of a more focused description, all of the various components ofthe laser unit are not shown, but a few components will be brieflydescribed. For example, laser 101 includes an optical pickup unit or“pick-up head” including the semiconductor laser, a lens for guiding thelaser beam, and photodiodes for detecting the light reflection fromdisc's surface. Two or more servomechanisms may be used to keep adistance of lens to disc, to ensure a laser beam is focused on a smalllaser spot on a disc, and to move the head along a disc's radius.

Numerous parameters of a laser can be adjusted and calibrated accordingto design goals for good writing performance. Example writing parametersof a laser include the power of the laser, the laser focus depth, thetilt of the objective lens, the radial offset, and write strategyparameters such as the width distribution, the interval between pulses,peakedness, amplitude, phase, frequency, inter-pulse separation, switchspeed, the length or width of the pits and lands, and user-definedparameters, among many others. Certain laser parameters may produceimproved quality with one type or brand of recordable media, whereasanother set of parameters may work better with another type or brand ofrecordable media.

Firmware 102 controls laser 101. For example, firmware 102 may identifythe type of recordable media, compute performance characteristics andparameters of the laser, perform mathematical operations, and controloptical drive 100 so as to calibrate or re-calibrate the writingparameters of laser 101. Of course, firmware 102 may control variousother processes in optical drive 100, such as disc loading and ejectionand input/output.

Disc 150 is one example of a recordable medium that can be written to byoptical drive 100. Numerous embodiments of disc 150 are possible,including a recordable CD-R, DVD-R, DVD+R, BD-R or HD DVD-R disc,rewritable CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE, HD DVD-RW, or HDDVD-RAM discs, and double-sided or double-layer versions of the above,among others.

Various manufacturers construct such recordable media, andcharacteristics of a disc often vary according to the manufacturer. Toaid in writing to the medium, the manufacturer of disc 150 may includedata on disc 150 regarding characteristics of disc 150. For example,disc 150 may include a reserved area storing address in pre-groove(ADIP) information containing tolerance information for the disc, suchas the maximum level of laser power disc 150 can handle before producingunacceptable data. While ADIP information is thus useful inapproximating a tolerable range of writing parameters, the ADIPinformation does not contain writing parameters to compensate for aspecific optical drive and writing environment.

Therefore, an example process for calibrating writing parameters of alaser in an optical drive will now be described with respect to FIG. 2.

The process begins in step 201, where firmware 102 sets allowable rangesfor varying the laser writing parameters of laser 101. As mentionedabove, different recordable media can only tolerate certain ranges oflaser characteristics while still producing acceptable output. Thus, thefirmware sets the range of possible values for each laser writingparameter in accordance with disc 150, so that time and energy are notwasted by testing a laser writing parameter value which falls outside anallowable range. In one example embodiment, firmware 102 controls thelaser 101 to read ADIP information from the disc 150, and the ADIPinformation includes information concerning the range of possible valuesfor each writing parameter. Of course, other methods of accessing thisinformation are possible, such as downloading this information from anetwork or separate computer. Once the ranges for each writing parameterof laser 101 have been set for disc 150, testing can begin.

Accordingly, in step 202, firmware controls laser 101 so as to record apredesignated number of test runs on disc 150 while certain parametersof laser 101 are varied in accordance with well knownDesign-of-Experiment (DOE) principles. For example, the parameters canbe varied according to a Taguchi method or a Box-Behnken method, amongothers.

In one example embodiment, the number of test runs is based on thenumber of writing parameters that are being calibrated. Morespecifically, if a greater number of writing parameters are beingobserved and calibrated by firmware 102, a greater number of test runsmight be preferred. On the other hand, attempting to calibrate too manyparameters at once might lead to unacceptable computation time, use ofsystem resources, or physical space taken up on disc 150 for conductingadditional test runs. Of course, it is possible to construct opticaldrives that can handle more writing parameters at once.

In one example embodiment, laser 101 records the set number of test runsin test areas of disc 150 known as Error Correction Code (ECC) frames,so as not to take up space on disc 150 reserved for the user's data.

During the recording of the test runs, the selected variations of theparameters should be produced in a random order, so as to reduce oravoid inaccurate correlations between the output performancecharacteristics and conditions that are not based on writing parameters.For example, simply stepping laser power levels up in a linear fashionwould lead to unacceptable correlations between performancecharacteristics and, for example, laser temperature or time, rather thanthe writing parameters of laser 101.

After the test runs, firmware 102 evaluates the performancecharacteristics produced by each test run, and stores this data in amemory along with the laser writing parameters of the test run. Exampleperformance characteristics include the asymmetry of the HF signal whichrepresents the relation between the smallest and largest symbol in thesignal (or a similar parameter called “Beta” representing the relationbetween the AC and DC level of the HF signal), the block error rate(BLER), the amount of jitter, or various combinations of the run lengthsof various pulses of the EFM signal, among many others.

Thus, firmware 102 stores data corresponding to input writing parameterswhich produced each test run, and the output performance characteristicsof the test run. An illustrative example of such data is shown below inTable 1. In the example of Table 1, the writing parameters that werevaried include the laser power (“power”), the write pulse duration usinga castle write strategy for 3T marks (“ti3”), the initial pulse time(“ttop”), and the width of the last 4T pulse (“tlp4”). In the example ofTable 1, the measured performance characteristics are the symmetry ofthe HF signal (“beta”), the block error rate (“BLER”), the jitter, therun lengths of the pit and land for 3T marks (“3T pit” and “3T land”),and the run lengths of the pit and land for 4T marks (“4T pit” and “4Tland”).

In addition, Table 1 also depicts a value “Penalty” for each test run.This value is a composite penalty value that depends on a combination ofmultiple ones of the above performance characteristics. The penaltyfunction can differ in dependence on design goals for performance. Forexample, in keeping with one design goal, the penalty function mightdepend only on one performance characteristic such as BLER or jitter. Inother design goals, there might be a composite penalty function thatdepends on combinations of more than one performance characteristic. Inthis example embodiment, the “penalty” is calculated in accordance withthe following equation:P=Σ _(l) ^(n)(β_(l)−β)²+Σ_(l) ^(n)(3T _(ipit)−3T _(pit))²+Σ_(l) ^(n)(3T_(iland)−3T _(land))²+Σ_(l) ^(n)(4T _(ipit)−4T _(pit))²+Σ_(l) ^(n)(4T_(iland)−4T _(land))²

In the above example embodiment, β as well as 3T_(pit), 3T_(land),4T_(pit) and 4T_(land) are expressed in terms of power and other writestrategy parameters, and the variables with index “i” are measured data.As will be described further below, the objective of the overallprocedure is to find a combination of the write parameters which arevaried for which the penalty function P is minimum. In this particularexample embodiment, the penalty function is an excellent representationof the total jitter.

Table 1 also illustrates an introductory track for Optimum PowerCalibration (OPC) in which only the power of laser 101 is varied. TheOPC track is an optional variation in order to obtain baselinecharacteristics according to the power level. Of course, numerous otherparameters can be varied and numerous other characteristics can bemeasured, and neither the writing parameters nor the measuredperformance characteristics are limited to those shown in Table 1.

TABLE 1 Track Power ti3 ttop tlp4 beta BLEB Jitter 3T pit 3T land 4T pit4T land Penalty OPC 757 80 50 30 −4.8 19 10.3 −11.5 3.6 2.5 6.9 146 T1840 77 50 34 2.4 8 9.5 −8.1 0.2 2.4 8.1 19 T2 840 76 51 33 1.2 10 10.0−8.8 −0.4 1.9 8.1 26 T3 880 77 54 33 6.5 10 8.7 −6.8 −0.7 1.2 8.1 11 T4880 80 51 30 8.3 6 8.7 −2.0 −1.4 −2.4 7.8 34 T5 820 77 51 31 −0.4 7 9.9−10.6 0.9 1.9 8.0 56 T6 900 77 53 30 8.2 11 14.4 −5.7 −0.3 0.7 7.9 19 T7820 80 54 34 2.3 11 9.2 7.4 0.2 2.3 8.0 16 T8 900 76 54 31 7.2 77 8.7−7.4 −1.2 0.5 8.3 16 T9 820 76 50 30 −1.5 12 10.0 −11.5 1.4 1.9 8.0 79T10 900 80 50 33 9.9 8 9.0 −1.7 −1.4 −1.9 7.2 51 T11 900 79 51 34 9.4 68.7 −3.2 −1.4 −1.0 7.4 34 T12 840 80 53 31 4.7 8 8.2 −4.5 −0.3 −0.3 8.03 T13 820 79 53 33 1.8 9 9.0 −8.1 0.1 1.8 8.0 19 T14 880 79 50 31 7.6 78.3 −2.6 −0.9 −1.9 7.7 23 T15 840 79 54 30 4.0 6 8.1 −6.5 −0.4 0.1 8.0 2T16 880 76 53 34 5.7 21 9.2 −8.3 −1.0 1.8 8.0 17

In this regard, it is possible that not all writing parameters willproduce performance characteristics that are optimum, or evenacceptable. Therefore, the set of test runs must be narrowed down tothose test runs that produced acceptable values for the penaltyfunction.

Accordingly, in step 203, firmware 102 computes the penalty function forevery test run based on the measured performance characteristics, anddetermines whether any test run has produced a penalty function below apreset maximum.

If no test run has produced an acceptable penalty value (i.e. one belowthe maximum), it is ordinarily preferable to record another set of testruns, to attempt to obtain better performance characteristics. Thus, theprocess proceeds to step 209 to increment a run counter (not shown) andpotentially record another set of test runs. This process will bedescribed in more detail below. On the other hand, if at least one testrun produced a penalty value below the acceptable maximum, the processproceeds to step 204.

In step 204, firmware 102 chooses the test run which produced the bestvalue for the penalty function of the selected performancecharacteristics. For example, using the values in Table 1, test run T15will be selected because of its minimum penalty value.

In step 205, firmware 102 verifies that the correlation between theperformance characteristics and the writing parameters of the selectedtest run are acceptable, using any number of mathematical methodsavailable to one of skill in the art. If the correlation is notacceptable, the process proceeds to step 209. Otherwise, if thecorrelation is acceptable, the process proceeds to step 206.

In step 206, firmware 102 uses the writing parameters of the selectedtest run. Specifically, laser 101 is configured to the new writingparameters corresponding to the selected test run. Thus, subsequentwriting of actual data with the laser is performed according to thesenew writing parameters, and should lead to similarly improvedperformance characteristics.

Before writing data to the recordable medium, however, the process mayproceed to step 207, in which a confirmation track is written with thenew writing parameters. In this regard, step 207 is optional, since itcan be expected that the confirmation track will yield the sameperformance characteristics as the selected best test run. Theconfirmation track should be written in an ECC frame or other blank areaof the disc, so as not to interfere with disc space for data. Writingthe confirmation track provides an additional safeguard to help ensurethat the calibrated writing strategy parameters will yield an acceptableoutput.

In step 208, firmware 102 examines the confirmation track with laser 101to determine whether the quality of the output is acceptable. If, forany reason, the quality of the confirmation track is unsatisfactory,then no data should be written to the disc with these parameters, andthe process proceeds to step 209 to re-run the tests. On the other hand,if the quality of the confirmation track is acceptable, then the writinglaser can proceed to write data to the recordable medium according tothe new writing parameters.

Thus, according to the above steps, firmware 102 calibrates the writingparameters of laser 101, based on the test runs conducted with disc 150.

As indicated above, if one or more characteristics of a set of test runsis unacceptable, the process proceeds to step 209. For example, theprocess proceeds to step 209 when penalty function values are too highfor all test runs, or if no selected performance characteristics areacceptable for any of the test runs. In such a situation, it mightuseful to try again with one or more extra sets of test runs, in orderto determine better parameters for the laser, if possible.

First, however, firmware 102 increments a run counter in step 209. Thepurpose of the counter is to ensure that the test run process does notcontinue indefinitely. In particular, the type of media simply may notcorrespond well with optical drive 100, and it may be impossible,unlikely, or too time-consuming to reach a test run that yields optimumoutput. Thus, a counter keeps track of how many cycles of test runs havebeen completed, and a maximum value of cycles is set as a “cut-off” forfurther sets of test runs.

If it is determined in step 210 that the run limit has not yet beenreached, the process proceeds to step 201 to re-set the parameter rangesfor testing, and the calibration process repeats. If, on the other hand,the run limit has been reached, then the process continues to step 211.

In step 211, firmware 102 retrieves the test run with the bestperformance characteristics from the test runs conducted before the runlimit was reached, and uses them. Accordingly, even in a worst-casescenario, it is still likely that laser 101 is calibrated to writingparameter values at least as good as that if no calibration had beenconducted at all.

Another example process for calibrating a writing laser will now bedescribed with respect to FIG. 3. In this regard, certain steps maycorrespond similarly to steps described above with respect to FIG. 2,and thus, for purposes of simplicity, corresponding details will not bedescribed again.

The process begins in step 301, where firmware 102 sets ranges for thelaser writing parameters based on disc 150.

In step 302, firmware controls laser 101 so as to record a set number oftest runs on disc 150 while varying the parameters of laser 101 withinthe allowable ranges according to a DOE method, as described above.

In step 303, firmware 102 computes a penalty value for each test run anddetermines whether the minimum penalty value selected from all test runsfalls below a preset maximum. As discussed above, the nature of thepenalty function can vary in dependence on design goals, and can dependon various combinations of performance characteristics. If no test runshave produced a penalty value below the acceptable maximum, the processproceeds to step 309. On the other hand, if at least one test runproduced a penalty value below the acceptable maximum, the processproceeds to step 304.

In step 304, firmware 102 uses numerical regression or anothermathematical approximation to calculate an estimate of writingparameters that will produce the best possible values for the penaltyfunction. Thus, rather than selecting a single best run, as in theexample of FIG. 2, the process mathematically approximates the “best”writing parameters by minimizing the penalty function. This can beaccomplished by several mathematical methods including, for example,interpolation, the method of least squares, and so on.

The selected performance characteristics, of course, influence theoutcome of the approximation. For example, firmware 102 could calculatea penalty function so as to minimize jitter, whereas another penaltyfunction could be computed so as to minimize BLER, or even a combinationof several performance characteristics. In any case, once firmware 102estimates projected values for the writing parameters, the processproceeds to step 305.

In step 305, firmware 102 determines whether the writing parametersestimated in step 306 are within the allowable range of writingparameters for disc 150. Put another way, firmware 102 must verify thatthe estimated writing parameters are actually usable on disc 150. Forexample, firmware 102 may estimate a power level of 20 mW in step 306,whereas disc 150 can only handle up to 15 mW (as indicated, for example,by the disc's ADIP information). If the estimated values fall outsidethe possible range of parameters, the parameters cannot be used, and theprocess proceeds to step 309 to (potentially) re-record another set oftest runs. On the other hand, if the estimated parameters fall withinthe allowable ranges, the process proceeds to step 306.

In step 306, firmware 102 uses the calculated writing parameters.Specifically, laser 101 is configured to the calculated writingparameters. Thus, subsequent writing of actual data with the laser isperformed according to these characteristics, and should lead to theimproved performance characteristics estimated by firmware 102.

Before proceeding with writing data to the recordable medium, however,the process proceeds to step 307, in which a continuation track iswritten with the new writing parameters. For example, using the methodof least squares for regression and the values from the test runs T1 toT16 in Table 1, one might arrive at the following confirmation trackwriting parameters and performance characteristics:

Track Power Ti3 Ttop Tip4 Beta BLEB Jitter 3T pit 3T land 4T pit 4T landPenalty Con 829 81 55 30 5.1 16 8.3 −4.4 −0.6 −0.5 8.0 2

In step 308, the confirmation track is examined to determine whether thequality of the output produced using the calibrated writing parametersis acceptable. If the quality of the confirmation track isunsatisfactory, the process proceeds to step 309 to re-run the tests. Inthis regard, steps 309 to 311 correspond similarly to steps 209 to 211,and accordingly will not be described here further.

On the other hand, if the quality of the confirmation track isacceptable, then the process ends, and the writing laser can proceed towrite data to the recordable medium according to the new laser writingparameters.

By virtue of the above-described example embodiments, it is ordinarilypossible to improve performance characteristics of the writing laser bycalibrating various parameters of the writing laser in the opticaldrive, thus allowing for the writing parameters of the laser to be setand re-set after manufacture according to differences in the recordingenvironment.

Referring now to FIGS. 4A-4H, various exemplary implementations of thepresent invention are shown. Referring to FIG. 4A, the present inventionmay be embodied in a hard disk drive system (HDD) 1500. The presentinvention may implement either or both signal processing and/or controlcircuits, which are generally identified in FIG. 4A at 1502. In someimplementations, signal processing and/or control circuit 1502 and/orother circuits (not shown) in HDD 1500 may process data, perform codingand/or encryption, perform calculations, and/or format data that isoutput to and/or received from a magnetic storage medium 1506.

HDD 1500 may communicate with a host device (not shown) such as acomputer, mobile computing devices such as personal digital assistants,cellular phones, media or MP3 players and the like, and/or other devicesvia one or more wired or wireless communication links 1508. HDD 1500 maybe connected to memory 1509, such as random access memory (RAM), a lowlatency nonvolatile memory such as flash memory, read only memory (ROM)and/or other suitable electronic data storage.

Referring now to FIG. 4B, the present invention may be embodied in adigital versatile disc (DVD) drive 1510. The present invention mayimplement either or both signal processing and/or control circuits,which are generally identified in FIG. 4B at 1512, and/or mass datastorage 1518 of DVD drive 1510. Signal processing and/or control circuit1512 and/or other circuits (not shown) in DVD 1510 may process data,perform coding and/or encryption, perform calculations, and/or formatdata that is read from and/or data written to an optical storage medium1516. In some implementations, signal processing and/or control circuit1512 and/or other circuits (not shown) in DVD 1510 can also performother functions such as encoding and/or decoding and/or any other signalprocessing functions associated with a DVD drive.

DVD drive 1510 may communicate with an output device (not shown) such asa computer, television or other device via one or more wired or wirelesscommunication links 1517. DVD 1510 may communicate with mass datastorage 1518 that stores data in a nonvolatile manner. Mass data storage1518 may include a hard disk drive system (HDD) such as that shown inFIG. 4A. The HDD may be a mini HDD that includes one or more plattershaving a diameter that is smaller than approximately 1.8″. DVD 1510 maybe connected to memory 1519, such as RAM, ROM, low latency nonvolatilememory such as flash memory, and/or other suitable electronic datastorage.

Referring now to FIG. 4C, the present invention may be embodied in ahigh definition television (HDTV) 1520. The present invention mayimplement either or both signal processing and/or control circuits,which are generally identified in FIG. 4C at 1522, a WLAN interfaceand/or mass data storage of the HDTV 1520. HDTV 1520 receives HDTV inputsignals in either a wired or wireless format and generates HDTV outputsignals for a display 1526. In some implementations, signal processingcircuit and/or control circuit 1522 and/or other circuits (not shown) ofHDTV 1520 may process data, perform coding and/or encryption, performcalculations, format data and/or perform any other type of HDTVprocessing that may be required.

HDTV 1520 may communicate with mass data storage 1527 that stores datain a nonvolatile manner such as optical and/or magnetic storage devices.At least one hard disk drive system (HDD) may have the configurationshown in FIG. 4A and/or at least one DVD may have the configurationshown in FIG. 4B. The HDD may be a mini HDD that includes one or moreplatters having a diameter that is smaller than approximately 1.8″. HDTV1520 may be connected to memory 1528 such as RAM, ROM, low latencynonvolatile memory such as flash memory and/or other suitable electronicdata storage. HDTV 1520 also may support connections with a WLAN via aWLAN network interface 1529.

Referring now to FIG. 4D, the present invention may be embodied in acontrol system of a vehicle 1530, a WLAN interface and/or mass datastorage of the vehicle control system. In some implementations, thepresent invention implements a powertrain control system 1532 thatreceives inputs from one or more sensors such as temperature sensors,pressure sensors, rotational sensors, airflow sensors and/or any othersuitable sensors and/or that generates one or more output controlsignals such as engine operating parameters, transmission operatingparameters, and/or other control signals.

The present invention may also be embodied in other control systems 1540of vehicle 1530. Control system 1540 may likewise receive signals frominput sensors 1542 and/or output control signals to one or more outputdevices 1544. In some implementations, control system 1540 may be partof an anti-lock braking system (ABS), a navigation system, a telematicssystem, a vehicle telematics system, a lane departure system, anadaptive cruise control system, a vehicle entertainment system such as astereo, DVD, compact disc and the like. Still other implementations arecontemplated.

Powertrain control system 1532 may communicate with mass data storage1546 that stores data in a nonvolatile manner. Mass data storage 1546may include optical and/or magnetic storage devices for example a harddisk drive system (HDD) and/or DVDs. At least one HDD may have theconfiguration shown in FIG. 4A and/or at least one DVD may have theconfiguration shown in FIG. 4B. The HDD may be a mini HDD that includesone or more platters having a diameter that is smaller thanapproximately 1.8″. Powertrain control system 1532 may be connected tomemory 1547 such as RAM, ROM, low latency nonvolatile memory such asflash memory and/or other suitable electronic data storage. Powertraincontrol system 1532 also may support connections with a WLAN via a WLANnetwork interface 1548. The control system 1540 may also include massdata storage, memory and/or a WLAN interface (all not shown).

Referring now to FIG. 4E, the present invention may be embodied in acellular phone system 1550 that may include a cellular antenna 1551. Thepresent invention may implement either or both signal processing and/orcontrol circuits, which are generally identified in FIG. 4E at 1552, aWLAN interface and/or mass data storage of the cellular phone system1550. In some implementations, cellular phone system 1550 includes amicrophone 1556, an audio output 1558 such as a speaker and/or audiooutput jack, a display 1560 and/or an input device 1562 such as akeypad, pointing device, voice actuation and/or other input device.Signal processing and/or control circuits 1552 and/or other circuits(not shown) in cellular phone system 1550 may process data, performcoding and/or encryption, perform calculations, format data and/orperform other cellular phone system functions.

Cellular phone system 1550 may communicate with mass data storage 1564that stores data in a nonvolatile manner such as optical and/or magneticstorage devices for example a hard disk drive system (HDD) and/or DVDs.At least one HDD may have the configuration shown in FIG. 4A and/or atleast one DVD may have the configuration shown in FIG. 4B. The HDD maybe a mini HDD that includes one or more platters having a diameter thatis smaller than approximately 1.8″. Cellular phone system 1550 may beconnected to memory 1566 such as RAM, ROM, low latency nonvolatilememory such as flash memory and/or other suitable electronic datastorage. Cellular phone system 1550 also may support connections with aWLAN via a WLAN network interface 1568.

Referring now to FIG. 4F, the present invention may be embodied in a settop box 1580. The present invention may implement either or both signalprocessing and/or control circuits, which are generally identified inFIG. 4F at 1584, a WLAN interface and/or mass data storage of the settop box 1580. Set top box 1580 receives signals from a source such as abroadband source and outputs standard and/or high definition audio/videosignals suitable for a display 1588 such as a television and/or monitorand/or other video and/or audio output devices. Signal processing and/orcontrol circuits 1584 and/or other circuits (not shown) of the set topbox 1580 may process data, perform coding and/or encryption, performcalculations, format data and/or perform any other set top box function.

Set top box 1580 may communicate with mass data storage 1590 that storesdata in a nonvolatile manner. Mass data storage 1590 may include opticaland/or magnetic storage devices for example a hard disk drive system(HDD) and/or DVDs. At least one HDD may have the configuration shown inFIG. 4A and/or at least one DVD may have the configuration shown in FIG.4B. The HDD may be a mini HDD that includes one or more platters havinga diameter that is smaller than approximately 1.8″. Set top box 1580 maybe connected to memory 1594 such as RAM, ROM, low latency nonvolatilememory such as flash memory and/or other suitable electronic datastorage. Set top box 1580 also may support connections with a WLAN via aWLAN network interface 1596.

Referring now to FIG. 4G, the present invention may be embodied in amedia player 600. The present invention may implement either or bothsignal processing and/or control circuits, which are generallyidentified in FIG. 4G at 604, a WLAN interface and/or mass data storageof the media player 600. In some implementations, media player 600includes a display 607 and/or a user input 608 such as a keypad,touchpad and the like. In some implementations, media player 600 mayemploy a graphical user interface (GUI) that typically employs menus,drop down menus, icons and/or a point-and-click interface via display607 and/or user input 608. Media player 600 further includes an audiooutput 609 such as a speaker and/or audio output jack. Signal processingand/or control circuits 604 and/or other circuits (not shown) of mediaplayer 600 may process data, perform coding and/or encryption, performcalculations, format data and/or perform any other media playerfunction.

Media player 600 may communicate with mass data storage 610 that storesdata such as compressed audio and/or video content in a nonvolatilemanner. In some implementations, the compressed audio files includefiles that are compliant with MP3 format or other suitable compressedaudio and/or video formats. The mass data storage may include opticaland/or magnetic storage devices for example a hard disk drive system(HDD) and/or DVDs. At least one HDD may have the configuration shown inFIG. 4A and/or at least one DVD may have the configuration shown in FIG.4B. The HDD may be a mini HDD that includes one or more platters havinga diameter that is smaller than approximately 1.8″. Media player 600 maybe connected to memory 614 such as RAM, ROM, low latency nonvolatilememory such as flash memory and/or other suitable electronic datastorage. Media player 600 also may support connections with a WLAN via aWLAN network interface 616. Still other implementations in addition tothose described above are contemplated.

Referring to FIG. 4H, the present invention may be embodied in a Voiceover Internet Protocol (VoIP) phone 620 that may include an antenna 621.The present invention may implement either or both signal processingand/or control circuits, which are generally identified in FIG. 4H at622, a wireless interface and/or mass data storage of the VoIP phone623. In some implementations, VoIP phone 620 includes, in part, amicrophone 624, an audio output 625 such as a speaker and/or audiooutput jack, a display monitor 626, an input device 627 such as akeypad, pointing device, voice actuation and/or other input devices, anda Wireless Fidelity (Wi-Fi) communication module 628. Signal processingand/or control circuits 622 and/or other circuits (not shown) in VoIPphone 620 may process data, perform coding and/or encryption, performcalculations, format data and/or perform other VoIP phone functions.

VoIP phone 620 may communicate with mass data storage 623 that storesdata in a nonvolatile manner such as optical and/or magnetic storagedevices, for example a hard disk drive system (HDD) and/or DVDs. Atleast one HDD may have the configuration shown in FIG. 4A and/or atleast one DVD may have the configuration shown in FIG. 4B. The HDD maybe a mini HDD that includes one or more platters having a diameter thatis smaller than approximately 1.8″. VoIP phone 620 may be connected tomemory 629, which may be a RAM, ROM, low latency nonvolatile memory suchas flash memory and/or other suitable electronic data storage. VoIPphone 620 is configured to establish communications link with a VoIPnetwork (not shown) via Wi-Fi communication module 628.

Example aspects of the disclosure have been described above with respectto particular illustrative embodiments. It is understood that thedisclosure is not limited to the above-described embodiments and thatvarious changes and modifications may be made by those skilled in therelevant art without departing from the spirit and scope of thedisclosure.

What is claimed is:
 1. A method for calibrating write parameters in anoptical drive, the method comprising: measuring each write performancecharacteristic corresponding to each of a plurality of test runsrecorded on a recordable medium; determining a value calculated bysquaring value differences between run lengths of pits or between runlengths of lands of the recordable medium during each of the test runs;and selecting actual write parameters for use in writing actual databased on the value.
 2. The method according to claim 1, furthercomprising: setting a parameter range for the write parameters based onthe recordable medium.
 3. The method according to claim 2, furthercomprising: verifying that the write parameters are within the setparameter range.
 4. The method according to claim 1, further comprising:varying the write parameters while recording the test runs on therecordable medium.
 5. The method according to claim 4, wherein the writeparameters are varied according to a Design-of-Experiments (DOE)methodology.
 6. The method according to claim 1, wherein the writeparameters are selected based on a test run which includes a bestvalue(s).
 7. The method according to claim 1, further comprising:calibrating a laser of the optical drive according to a numericalinterpolation of the write parameters.
 8. The method according to claim1, further comprising: recording a confirmation track according to theselected actual write parameters; and confirming that the performancecharacteristics fall within a predefined range.
 9. The method accordingto claim 1, wherein the actual write parameters are selected so as tominimize the value.
 10. The method according to claim 1, furthercomprising: counting a number of the test runs.
 11. An apparatus forcalibrating write parameters in an optical drive, the apparatuscomprising: a measuring unit configured to measure each writeperformance characteristic corresponding to each of a plurality of testruns recorded on a recordable medium, and determine a value calculatedby squaring value differences between run lengths of pits or between runlengths of lands of the recordable medium during each of the test runs;and a selecting unit configured to select actual write parameters foruse in writing actual data, based on the value.
 12. The apparatusaccording to claim 11, further comprising: a setting unit configured toset a parameter range for the write parameters based on the recordablemedium.
 13. The apparatus according to claim 12, further comprising: averification unit configured to verify that the write parameters arewithin the set parameter range.
 14. The apparatus according to claim 11,further comprising: a recording unit configured to vary the writeparameters while recording the test runs on the recordable medium. 15.The apparatus according to claim 14, wherein the write parameters arevaried according to a Design-of-Experiments (DOE) methodology.
 16. Theapparatus according to claim 11, wherein the write parameters areselected based on a test run which includes a best value(s).
 17. Theapparatus according to claim 11, wherein a laser of the optical drive iscalibrated according to a numerical interpolation of the writeparameters.
 18. The apparatus according to claim 11, wherein the actualwrite parameters are selected so as to minimize the value.
 19. Theapparatus according to claim 11, further comprising: a run counter forcounting a number of the test runs.